This research project is concerned with an intensive investigation of the phenomenological behavior and kinetic stabilities of steady states in poly-d (AT) synthesis from the nucleotide triphosphates in the presence of template-primer and DNA-Polymerase I. The experimental method proposed for the first time for a biochemical reaction is that of the stirred flow reactor. The stirred flow reactor is an ideal tool to maintain steady states indefinitely by in-flow of material from the outside, permitting a convenient study of intermediates in the reaction. The attainment of the steady state will be measured spectrophotometrically at 260 nm inside the stirred flow reactor. Since the synthesis is autocatalytic in its early stages, the potential for oscillations in polymer concentrations and for multiple steady states exists. Multiple steady states provide a certain synthesizing flexibility. The important question arises which steady state the system will prefer under open, flow conditions and what the concentration and composition of the synthetized polymer is at each steady state. Another question concerns the incorporation of wrong bases (error rate) at specific steady states. Such studies are important for our understanding of evolutionary processes at the macromolecular level. The investigation of the properties of steady states in poly-d (AT) synthesis will include the following: Perturbation of a steady state by injection of monomer, primer or enzyme concentrations, incorporation of wrong bases and the effect of mutagenic agents. The kinetics of the synthesis will be investigated in static reactions as well. The combined information of flow and static experiments will culminate in a proposed mechanism for synthesis and degradation. Application of the principles of nonlinear irreversible thermodynamics will be made.